Chapter 3 Types of Thermogravimetric Analyzers (TGA)

There are three types of thermogravimetric analyzers: suspension system, top-loading system and horizontal system.

Structures and Features

Suspension system Top-loading system Horizontal system
sample
A sample is suspended from the analyzer. A sample is placed above the analyzer. A sample is placed at the edge of the analyzer.
  • Highly sensitive thermogravimetry
  • Wide range of measurable sample volumes
  • Simultaneous measurement of TG-DTA and TG-DSC is not possible.
  • Direct measurements of sample temperatures are possible.
  • Can be applied as simultaneous measuring devices of TG-DTA and TG-DSC.

 

In general, baselines drift in TG analysis when temperatures fluctuate due to changes in buoyancy and convection by heating. (Weight signals change even if the amount of sample does not change superficially.) In order to avoid baseline drifts, analyzers with differential structures are often used in each system.

 

What is a Differential Structure?

Example of DTG-60 Differential Thermal Analyzer with Top-Loading System

The following image shows the structure of a top-loading differential analyzer.

As shown in the image, when a sample and a reference are placed on sample trays (temperature sensors) located at both edges of a beam and heated, a weight difference between the sample and the reference is detected as a signal. Since buoyancy and convection are applied equally to them, the force is offset to remove the baseline drift.